charles.harbert wrote:

Al, I know that part of the reason the primary injectors are placed near the
port is to avoid hesitation because the air moves faster than the fuel, so you
can get a lean stumble when opening the throttle plates. It's the same reason
they have an accelerator pump on a carb. Also, by injecting the fuel into the
port, as opposed to the intake tube, you get better piston (rotor) cooling
because the big negative heat of vaporization. If you look at Mazda's design
they have the secondary hi-spd injectors about 6" from the engine port. These
only open under hi-flow conditions (abv 3500 rpm) where the air velocity is high
enough to mix the fuel and vaporize it, but the majority of the cooling is in
the engine, not in the hot manifold.

I know aircraft engines will run with the injectors placed a long ways from the
port, but I think that it may not be an efficient way to develop power. I
understand that the dyno confirms this to be true. I'm sure this memo will cause
people to defend the injectors being located far away, but that's what this
forum is all about.

 
The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org